By Matt Burdett, 17 April 2018.
On this page, we look at characteristics of urban places, including site, function, land use, hierarchy of settlement (including megacities) and growth process (planned or spontaneous).
- Tokyo, Japan. One of the world’s largest urban centres – but not the biggest, depending on how ‘urban’ is measured.
What is an ‘urban’ place?
Essentially ‘urban’ means a built up area such as a town or city. There is no internationally agreed definition of what urban means. Each country has its own, such as:
- China: since 2001 China has used a system of ‘statistical classification’ meaning that the definition of an ‘urban’ area is not fixed. Instead, it can change depending on the way the data is collected (National Bureau of Statistics of China, 2002, and Beijing Municipal Bureau of Statistics, 2018)
- Kenya: a “built-up and compact human settlement with a population of at least 2,000
- people defined without regard to the local authority boundaries” (Kenya National Bureau of Statistics, 2012)
- United Kingdom – “areas of urban land use of 20 hectares or more with 1,500 or more residents” (ONS, 2016)
- United States: the US considers urban to refer to two types of area – Urbanized Areas (UAs) of 50,000 or more people, and Urban Clusters (UCs) of at least 2,500 and less than 50,000 people (US Census Bureau, 2016)
These definitions generally refer to population size and density. Other ways of classifying a place as urban are by the characteristics of an urban place, such as function, land use, hierarchy of settlement, and how the area grows.
Characteristics of urban places
Aside from the population, urban places also have common characteristics. Think of ‘urban’ and many people think of roads, buildings and infrastructure like electricity cables and sewage systems. Others will think of shops, offices and busy transport hubs.
Site refers to the land on which a settlement is built. For example, it might be on gently sloping land, facing south, with well-draining soil, a water supply from a local spring, and on a river bend. These features would all make it a good site for an early settlement in the pre-industrial age:
- gently sloping land – prevents flooding
- facing south – in the northern hemisphere, it means the settlement will be warmed by the sun during the day (also good for growing crops locally)
- with well-draining soil – so it’s easy to build on
- a water supply from a local spring – for drinking etc.
- on a river bend – provides a defensive barrier from attack
As urban areas have grown, site factors have become less important. For example, most cities do not source their water locally (from springs and rivers) but receive it in pipes from elsewhere. In the modern age, most urban areas are still found in places that have good ‘site’ features, but this is not because of the features of the site itself.
Situation refers to the location of the settlement in relation to what is around it. For example, a city might be located along a coastline, at the end of a river valley, at the other end of which is a coalfield. These features would all make a good place for a modern settlement because of the things nearby:
- located along a coastline – can build a port for international trade
- deep sea – allows large container ships to come into the port
- at the end of a river valley – valleys are important passages through mountains as they can be used for railways and roads
- near a coalfield – a cheap source of energy, and/or a product for export
In reality, a combination of good site and situation features are needed for a settlement to grow into a large urban area.
Function refers to ‘what the places does’, or ‘the reason the city is there’. Almost all settlements have more than one function, and the larger the urban area the more functions it is likely to have.
Typical functions of urban function include:
- Administrative centres – headquarters for government offices
- Transport – ports, railway junctions, airline hubs
- Markets – places where agricultural products made in the surrounding area can be sold
- Financial – headquarters of major banks, insurance companies etc.
Functions are both cause and effect of a city’s growth. For example, Hong Kong grew to its current population of over 7 million because it had a historical administrative function, as well as a transport function as a sea port. Over time it has grown into a financial centre, a retail centre and an airline transport hub. This is a good example of cumulative causation.
Land use in urban areas is easily identifiable as not rural meaning there is little agricultural land use. (There are no farms.)
Land use is often closely linked to the function. In almost all urban areas, residential is the main land use. In industrial centres, industrial land use will be common, and so on. However there are land use types that are not necessarily a function of the urban area, but are closely linked:
- Open space – parks, riversides, ‘empty’ places awaiting development
- Sports facilities – informal (such as parks) and formal (such as football stadia)
- Local transport – roads, railways, metro systems for moving local people around
- Government services and social amenities – libraries, schools, hospitals
- Infrastructure – telephone exchanges, data centres (for internet servers), gas terminals and so on
Hierarchy of settlement (including megacities)
A hierarchy refers to something put into a particular order, for example biggest to smallest. The settlement hierarchy is a way to classify settlements.
- An example of a settlement hierarchy. Source: By the author.
The names and types of the settlements that can be placed in the hierarchy vary. Some common types of settlements are:
- Isolate – an individual dwelling e.g. a farmhouse
- Hamlet – a small collection of dwellings (like a very small village)
- Village – a small settlement
- Town – varying in size from a few thousand people to several tens of thousands, depending on the characteristics of the town
- City – a large urban settlement
- Capital city – usually but not always the largest settlement in a country (e.g. London, Paris, Beijing); and/or the centre of national government (Brasilia, Canberra, Pretoria)
- Primate city – the name given to a country’s biggest city when it is at least twice as large as the next biggest city
- Binary city – the name given to a country’s two biggest cities when they are of roughly equal importance, e.g. Rio de Janeiro and Sao Paulo, Sydney and Melbourne, or Cape Town and Johannesburg
- Millionaire city – a city of at least one million people
- Megacity – a city of at least 10 million people
- Metacity / hypercity / megalopolis – a city of at least 20 million people (UN Habitat, 2006). These terms are also used to describe large conurbations such as the Pearl River Delta area in southern China.
- Conurbation – an urban area created when two or more large settlements grow so big that they join together
For more detail on megacities, see the dedicated pages on this site.
A note on economic settlement hierarchies
Settlements may also be classified into a hierarchy according to the variation of economic activity in a settlement. For example, a village may have only basic services and no industry at all, while a city may have a great mixture of economic activities. This generally relates to the size of the settlement as measured by population, but not always. For this reason, the hierarchy of settlements as classified by economic activity is covered in the ‘Urban Economic Activities’ section of this site.
Growth process (planned or spontaneous)
Historically cities have developed spontaneously – meaning their growth has not been planned. A combination of natural increase and in-migration from rural areas led to the increase in population in cities. This is still the case for cities in the poorest countries. Cities in the lowest income countries frequently have rapid and spontaneous urban development. Migration and a high rate of population growth result in a shortage of adequate housing, so people are forced to build their own dwellings. These areas are sometimes known as slums, shanty towns, favelas and bustees but are properly known as squatter settlements.
In general, modern cities in richest countries are carefully planned. Population growth in these High Income Countries is generally slow or in decline and is monitored by governments which then plan for the future needs of people in the cities. These cities often have strong administrations that are capable of managing changes such as infrastructure development.
Over the past half century, cities have increasingly been developed through deliberate planning by governments of countries at all income levels. These new settlements are often called ‘planned cities’ or ‘new towns’. They are defined by being largely planned in advance, rather than being additions to existing towns or cities. As existing cities became too big, governments create new cities for people to move to. They do this by denying planning permission on the edges of the bigger cities while granting it in the new town area, and by paying for the basic infrastructure in the new places (e.g. building highways, electricity and water services, schools and hospitals). However, they are often found nearby to existing cities. One of the most famous is Milton Keynes (near London, UK), but examples can be found across the world including Olgiata (near Rome, Italy), and Ma On Shan (Hong Kong). Canberra and Brasilia, the capital cities of Australia and Brazil respectively, are also both examples of planned cities.
Beijing Municipal Bureau of Statistics, 2018. Permanent Population (1978-2016). http://www.bjstats.gov.cn/English/MR/Population/201802/t20180201_392013.html
Kenya National Bureau of Statistics, 2012. Kenya Population and Housing Census. Analytical Report on Urbanization, Volume VIII, March 2012. https://www.knbs.or.ke/download/analytical-report-on-urbanization-volume-viii-2/
National Bureau of Statistics of China, 2002. Population.